Hardfork/upgrade trigger

[svyatonik]

Case: BCH Nov2018 HF adds new consensus rule - all transactions must have a serialized size > 100 bytes. If memory pool contains some transactions of size < 100 bytes BEFORE HF happens, they became invalid after HF, but will stay in memory pool.

Solution: we should have some upgrade/HF trigger that clears memory pool/reverifies all memory pool transactions when HF happens.

[debris]

they became invalid after HF, but will stay in memory pool.

I am not sure I understand. Why should they stay in memory pool?

[svyatonik]

They should not, but right they are staying in current implementation. We only remove transactions that are included in the block && transactions that are relying on inputs that are spent by transactions in the block. So idea is: when something global (here: consensus rules) changes, we need to reverify all memory pool transactions => this will remove all transactions that became invalid after this change.

[svyatonik]

Source code reference: https://github.com/paritytech/parity-bitcoin/blob/master/sync/src/synchronization_chain.rs#L379